PDMS gold nanoparticle composite film-based silver enhanced colorimetric detection of cardiac troponin I

This paper described poly(dimethylsiloxane) (PDMS)-gold nanoparticles (AuNPs) composite film as basis with silver enhancement for colorimetric detection of cardiac troponin I (cTnI). Stable PDMS-AuNPs composite film was simply prepared with dropping HAuCl4 solution in PDMS microchip, gold nanoparticles were both used as nuclei for silver enhancement and as basis for adsorption of antibody, immunoassay was implemented after BSA blocking. Because of the inhibition ability difference for silver enhancement between BSA and antibody-antigen complex, darkness of silver deposition was relative to the amount of antigen. The proposed colorimetric method was applied for clinical sample cTnI detection, results were consistent with that from enzyme-linked immunosorbent assay (ELISA). The composite film could be coupled with digital transmission of images for remote monitoring system in diagnosis, food control, and environmental analysis.